The Environmental Protection Agency has now formally proposed to limit certain super-potent greenhouse gases from use in air conditioners, refrigerators, aerosols and foams in favor of safer, more climate-friendly alternatives. EPA’s action last week follows through on a commitment it made earlier this year to limit such powerful greenhouse gases. This is a significant step forward and a key part of the President’s Climate Action Plan.

These dangerous chemicals are part of a class of chemicals called hydrofluorocarbons, or HFCs. Some HFCs, like HFC-134, are particularly harmful because they have a global-warming potential thousands of times greater than carbon dioxide. They are used for cooling in motor vehicle air conditioning, refrigeration, and vending machines, as well as in aerosols and foam blowing agents. HFCs currently contribute about 5% of domestic global warming pollution. And if we don’t curb their use, harmful HFC pollution is expected to double by 2020 and nearly triple by 2030 in the United States, making them a major contributor to climate change.

EPA has the authority to act

Fortunately, Congress gave EPA the authority to deal with this problem as part of the 1990 Clean Air Act Amendments. Back then, the main chemicals used in the sectors in which HFCs are now used, such as refrigerants, aerosols and foams, were chlorofluorocarbons or CFCs. CFCs destroy the stratospheric ozone layer, and global attention to the dangers of the “ozone hole” led nations to collaborate to address their use under the Montreal Protocol. As a result, in 1990 Congress directed EPA to phase out use of CFCs and approve viable alternatives in a variety of sectors including refrigeration, air-conditioning, and aerosols.

Under the Clean Air Act, EPA must determine which chemicals can be used in place of ozone-depleting substances. Through its Significant New Alternatives Policy (SNAP) program, EPA approves substances for use in particular applications and manufacturers may only use the substitutes on the SNAP list.

So when EPA evaluates a potential alternative, it considers not only its potential to deplete the ozone layer, but also other impacts on health, welfare and the environment, including the compound’s global- warming potential. Similarly, when it adds other safer alternatives to its list, EPA also considers whether to pull more harmful substitutes off it.

From CFCs to HFCs

CFCs not only deplete stratospheric ozone, but are also powerful global-warming gases. And while some of their replacements leave the ozone layer intact, those replacements can still accelerate man-made warming of our atmosphere.

HCFCs, or hydrochlorofluorocarbons, were the first generation of CFC replacements. These chemicals were less harmful to the stratospheric ozone than CFCs, but still caused some harm to the ozone layer and, like CFCs, were also powerful greenhouse gases. HFCs arrived next as replacements for HCFCs, an improvement with respect to protecting the ozone layer but still powerful greenhouse gases.

The good news is that safer alternatives that protect both the ozone layer and climate now exist. In early July, EPA published a proposed rule to add a range of chemicals to the SNAP list that are safe for both the ozone layer and better for the climate. These include several hydrocarbons as well as HFC-32, a far less harmful type of HFC. EPA is proposing to approve these for use in a range of applications including air conditioners, heat pumps, refrigeration systems, freezers and vending machines.

And last week EPA proposed the next step, limiting use of the dangerous HFCs based on the availability of these chemicals recently proposed for addition to the SNAP list and other safer alternatives already on it. EPA estimates the climate benefits of the proposed changes are equivalent to reducing 31 to 42 million metric tons of carbon dioxide in 2020 or the annual emissions of between six and a half million to nearly nine million cars. The new EPA proposal limits HFC use in car air conditioners, commercial refrigeration, foam blowing and certain consumer aerosols.

But I like having my car cooled…

The good news is that EPA’s proposed rule won’t force people to drive without air-conditioning or make supermarkets do without refrigeration. EPA is limiting use of HFCs only where there is a safer alternative available. For cars, there is already a safe alternative on the market, HFO-1234yf, a refrigerant that has one three-hundredths the impact of the HFC currently in use. Some cars on the road today already have this safer alternative. Similarly, some businesses are using climate friendly refrigeration systems. But a widespread transition from the chemicals that threaten our climate to safe alternatives will not happen on its own. That’s why EPA’s regulation is so important.

We aren’t the only ones

Fortunately, the United States is not the only country making this transition. Europe has also put in place standards to move away from HFCs and Japan is considering doing so. And the nearly 200 countries that are part of the Montreal Protocol are considering using the agreement to make this transition worldwide. Last month, 400 country delegates, scientific, technical and legal experts, and industry and environmental observers met to discuss HFC super pollutants. As the United States, Europe, Japan and other nations help demonstrate the viability of safe alternatives, it will to easier to reach consensus within the Montreal Protocol to make the needed changes worldwide.

We will have suggestions for EPA about whether we can make this important transition more quickly and about the next steps EPA should take to further limit dangerous HFCs. But in the meantime, it is time to applaud EPA for the significant steps in its proposed rule.